Books in libraries are often handled much more that those held in private hands. As a result, libraries have developed ways of protecting and repairing materials for customer usage. Many of the alterations libraries make are damaging to the book, and most books so modified are no long considered collectible. Books from libraries should be described as such when buying and selling them.
One common description is to denote former library books as ex-library with the usual markings. Books so described can be expected to have one or more of the following defacements.